Agatha Christie diamond jewellery realises 49,725% increase

Two pieces of diamond jewellery belonging to Agatha Christie's mother have realised a combined total of 49,375 ($79,320) in a sale at Bonhams London.

The ring realised 21,875 ($35,141) up 337.5% against a 5,000 ($8,032) estimate, while the brooch beat its valuation of 8,000 ($12,851) by 237.5% to take 27,500.

The consignor found the jewellery in a locked box bought at an estate sale

Jennifer Grant, the consignor, acquired the pieces after buying a mysterious box at a sale of the writer's estate in 2006. She paid just 100 ($160), with the result working out at a 49,275% on her initial investment.

She commented prior to the sale: "I was thrilled to have stumbled upon my very own mystery.

"I always wondered what was locked inside the strongbox but I never dreamt it would be anything so exciting as diamonds - I could hardly breathe when I unwrapped the tissue paper and found them.

"As an Agatha Christie fan, it's wonderful to think that these items actually touched her life. I've enjoyed the jewellery greatly over the last four years but I don't wear it as much as it deserves. I thought - why not let someone else enjoy them."

Carole Gordon of Bonhams said: "We are very pleased to have been able to offer these two fine pieces, coming as they do not only with an illustrious provenance but with such a wonderful story of discovery by the vendor.

"The astonishing prices achieved today are just the icing on the cake".

The husband of Confessions of a Shopaholic author Sophia Kinsella bought the lots for her as a gift.

She commented: "I was bowled over by this incredible surprise. Agatha Christie is the hugest inspiration and source of pleasure to me. I've read all her books, many times over and I feel very moved at the idea of having a piece of jewellery that was once hers."